Current therapeutic approaches to cryptosporidiosis in immunocompromised patients.

Cryptosporidium parvum is a protozon which can cause a severe debilitating disease in immunocompromised patients. Animal models show that cellular immunity is the most important factor protecting against the development of the disease, but patients with a humoral immune deficiency are also at risk. In HIV-infected patients there is a clear relationship between disease severity and CD4-cell counts. The development of insight into the pathogenesis and of new agents is hampered by the lack of an in-vitro culture system. Prevention is of utmost importance because of the difficulties of therapy and the severity of the clinical disease which can develop. Oocysts are highly resistant to the commonly used disinfectants. HIV-infected patients with cryptosporidiosis not on antiretroviral therapy should commence it. Non-specific therapy with anti-diarrhoeal agents should be instituted. If no effect is seen, therapy with paromomycin 500 mg qds for 2-3 weeks should be started, followed by maintenance therapy with 500 mg bid to prevent a relapse.